*{
    margin: 0;
    padding: 0;
    list-style: none;
}
.shouye{
    padding-top: 10px;
    padding-left: 180px;
}
.btn{
    width: 60px;
    height: 30px;
    background-color: #00aaff;
    color: aliceblue;
}
ul{
    padding-top: 20px;
}
li{
    float: left;
    margin-right: 30px;
    padding-bottom: 30px;
}
.second{
    clear: left;
}
a{
    color: black;
    text-decoration: none;
}
a:hover{
    color: red;

}